If we look at the crypto industry there are certain things that are needed for the industry to mature. Besides dapp browsers, and decentralized exchanges, privacy is also very essential. Crypto projects working on privacy can be separated into three categories

Privacy coins: Privacy coins are cryptocurrencies that are built upon other platforms or protocols. One example is Monero (ticker XMR) which is built on CryptoNote.

Privacy protocols: Privacy protocols are used by other projects. Examples include enigma and Zcoin.

Privacy platforms: Privacy platforms are whole platforms or full blockchains which can be used as a foundation by other cryptos. Examples include Phore and particl.